1. Technical Field
The present disclosure relates to a capacitance to voltage converter and, in particular, to a capacitance to voltage converter having a loop for compensating common or differential mode input leakage current.
2. Description of the Related Art
Leakage currents often occur at the interconnections between integrated circuits. For example, if two circuits are implemented on different semiconductor dies, leakage currents often occur at the interconnections between the dies. The leakages cause drainage of current from various signals. As a result of the drainage, current leakages degrade signals, performance and operation of the integrated circuits.
For example, in conventional capacitance to voltage amplifiers, leakage currents have been observed to degrade the performance of the conventional capacitance to voltage amplifiers. Further, depending on the severity of the current leakage, a conventional capacitance to voltage amplifier may be shut down or altogether become inoperable. In differential circuits, every pair of currents can be modeled with a pair of differential currents (with the same value and different signs) plus two common mode currents (with same value and sign), as shown in Equation (1):                i1=i1, i2=i2icm=(i1+i2)/2, id=(i1−i2)i1=icm+id/2, i2=icm−id/2        
For simplicity, the document will refer separately to common mode leakage current and differential mode leakage current, without loss of generality.